Have 2 new codes now. P0171 and P0174.

I took readings for the sensors you listed iat idle, and the the rpm's you specified. I took video so you can see them in real time. Was too hard hold the gas, read the scanner, and write everything down at once. I'm uploading them now, and will post in a few minutes.

 

Here's the trims at idle, and at 2500

 

The MAF and upstream O2's at idle, and 1700

 

I'm going to change the fuel filter, and if I have time I'm going to give the MAF another cleaning. I'll check back.

 

Ugggghhh. FINALLY got it to run bad when pulling out. Stopped and hooked up the scanner. Only ran bad for a few seconds after that, but my scanner didn't record the data.

 

Looks like no vacuum leak

Looks like your MAF may be severely under reporting at 1700 rpm. You read 11g/s at 1700, I read 25 g/s and Les Myers (in an old thread) read 35. That could be it. Swap with a known good MAF if you have one or if not turn the truck off, unplug the MAF and start it up and see what your fuel trims are doing. Under those circumstances, the truck will determine the theoretical fuel delivery using other sensors in speed density mode.

George

 

With my other maf the reading went up to 1.7 lb/min at 1700, and .66 at idle on my 1st test.

While warming it up I found that there is a nut missing from one of the exhaust studs at the y pipe on the driver side.

I also took apart the old maf as well, so I could clean it better, and the rounded side of the bars were FILTHY.

 

You might want to check power and ground to the MAF, look at the link I posted below


George

 

... and check your air filter.


George

 

I'll check the air filter and the MAF power/ground tomorrow. My dmm doesn't have a hz setting. Would an oscilloscope suffice?